The NAHB Research Center along with Progressive Foam Technologies, the leader in siding insulation, today announced the results of a new report that details the moisture performance of various exterior wall constructions with elevated indoor winter humidity and seasonal moisture injections.
Craig Drumheller, NAHB Research Center senior energy engineer and principal author of the report, states that "Insulated vinyl siding demonstrated the best moisture performance in the study, with the overall driest wall assembly regardless of indoor moisture conditions."
A field investigation of nine different wood-framed wall assemblies was conducted to determine the moisture performance of various exterior wall constructions with elevated wintertime humidity in two seasonal phases (40-45% RH for typical winter, and 25-30% RH in the summer) levels and seasonal moisture injections between the cladding and sheathing over a 13-month period. The report compares the nine wall pairs' performance to each other and the two phases.
Stud bay temperatures and humidity were monitored as were moisture contents in the exterior sheathing and the studs. Insulated vinyl siding and brick came out as the two driest assemblies with the insulated vinyl siding being the least affected by orientation. Stucco clad walls represented the wettest wintertime sheathings. Most of the wall sections were greatly influenced by the indoor relative humidity; the only wall system that was somewhat immune to the indoor relative humidity was the insulated vinyl siding.
"We engineered our Fullback siding insulation to do both—reduce air and water infiltration from the outside, and allow for an effective release of water vapor and excess humidity from the inside," said Pat Culpepper, president. "The NAHB Research Center study verifies Fullback's superior moisture performance, which is a key consideration for building professionals and homeowners."